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lvm2/daemons/Makefile.in
Bryn M. Reeves 8b78982297 daemons: add dmfilemapd
Add a daemon that can be launched to monitor a group of regions
corresponding to the extents of a file, and to update the regions as the
file's allocation changes.

The daemon is intended to be started from a library interface, but can
also be run from the command line:

  dmfilemapd <fd> <group_id> <path> <mode> [<foreground>[<log_level>]]

Where fd is a file descriptor open on the mapped file, group_id is the
group identifier of the mapped group and mode is either "inode" or
"path". E.g.:

  # dmfilemapd 3 0 vm.img inode 1 3 3<vm.img
  ...

If foreground is non-zero, the daemon will not fork to run in the
background. If verbose is non-zero, libdm and daemon log messages will
be printed.

It is possible for the group identifier to change when regions are
re-mapped: this occurs when the group leader is deleted (regroup=1 in
dm_stats_update_regions_from_fd()), and another region is created before
the daemon has a chance to recreate the leader region.

The operation is inherently racey since there is currently no way to
atomically move or resize a dm_stats region while retaining its
region_id.

Detect this condition and update the group_id value stored in the
filemap monitor.

A function is also provided in the the stats API to launch the filemap
monitoring daemon:

  int dm_stats_start_filemapd(int fd, uint64_t group_id, const char *path,
                              dm_filemapd_mode_t mode, unsigned foreground,
                              unsigned verbose);

This carries out the first fork and execs dmfilemapd with the arguments
specified.

A dm_filemapd_mode_t value is specified by the mode argument: either
DM_FILEMAPD_FOLLOW_INODE, or DM_FILEMAPD_FOLLOW_PATH. A helper function,
dm_filemapd_mode_from_string(), is provided to parse a string containing
a valid mode name into the appropriate dm_filemapd_mode_t value.
2017-03-09 18:50:15 +00:00

64 lines
1.4 KiB
Makefile

#
# Copyright (C) 2004-2015 Red Hat, Inc. All rights reserved.
#
# This file is part of LVM2.
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions
# of the GNU General Public License v.2.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
srcdir = @srcdir@
top_srcdir = @top_srcdir@
top_builddir = @top_builddir@
.PHONY: dmeventd clvmd cmirrord lvmetad lvmpolld lvmlockd
ifneq ("@CLVMD@", "none")
SUBDIRS += clvmd
endif
ifeq ("@BUILD_CMIRRORD@", "yes")
SUBDIRS += cmirrord
endif
ifeq ("@BUILD_DMEVENTD@", "yes")
SUBDIRS += dmeventd
ifneq ("$(CFLOW_CMD)", "")
daemons.cflow: dmeventd.cflow
endif
endif
ifeq ("@BUILD_LVMETAD@", "yes")
SUBDIRS += lvmetad
endif
ifeq ("@BUILD_LVMPOLLD@", "yes")
SUBDIRS += lvmpolld
endif
ifeq ("@BUILD_LVMLOCKD@", "yes")
SUBDIRS += lvmlockd
endif
ifeq ("@BUILD_LVMDBUSD@", "yes")
SUBDIRS += lvmdbusd
endif
ifeq ("@BUILD_DMFILEMAPD@", "yes")
SUBDIRS += dmfilemapd
endif
ifeq ($(MAKECMDGOALS),distclean)
SUBDIRS = clvmd cmirrord dmeventd lvmetad lvmpolld lvmlockd lvmdbusd dmfilemapd
endif
include $(top_builddir)/make.tmpl
ifeq ("@BUILD_DMEVENTD@", "yes")
device-mapper: dmeventd.device-mapper
endif